Charles M. Collins

White Phosphorus Poisoning of Waterfowl in an Alaskan Salt Marsh

The cause of the yearly death of an estimated 1,000 to 2,000 migrating dabbling ducks (Anas spp.) and 10 to 50 swans (Cygnus buccinator and C. columbianus) has remained a mystery for the last ten years in Eagle River Flats (ERF), a 1,000 ha estuarine salt marsh near Anchorage, Alaska, used for artillery training by the U.S. Army. We have gathered evidence that the cause of this mortality is the highly toxic, incendiary munition white phosphorus (P4). The symptoms of poisoning we observed in wild ducks included lethargy, repeated drinking, and head shaking and rolling. Death was preceded by convulsions. Farm-reared mallards dosed with white phosphorus showed nearly identical behavioral symptoms to those of wild ducks that became sick in ERF. White phosphorus does not occur in nature but was found in both the sediments where dabbling ducks and swans feed and in the gizzards of all carcasses collected in ERF. We hypothesize that feeding waterfowl are ingesting small particles of the highly toxic, incendiary munition P4 stored in the bottom anoxic sediments of shallow salt marsh ponds.

Sampling for Explosives-Residues at Fort Greely, Alaska

Fort Greely, Alaska has an extensive complex of weapon training and testing areas located on lands withdrawn from the public domain under the Military Lands Withdrawal Act (PL106-65). The Army has pledged to implement a program to identify possible munitions contamination. Because of the large size (344,165,000 m2) of the high hazard impact areas, characterization of these constituents will be difficult. We used an authoritative sampling design to find locations most likely to contain explosives-residues on three impact areas. We focused our sampling on surface soils and collected multi-increment and discrete samples at locations of known firing events and from areas on the range that had craters, pieces of munitions, targets, or a designation as a firing point. In the two impact areas used primarily by the Army, RDX was the most frequently detected explosive. In the impact area that was also used by the Air Force, TNT was the most frequently detected explosive. Where detected, the explosives concentrations generally were low (<0.05 mg/kg) except in soils near low-order detonations, where the explosive-filler was in contact with the soil surface. These low-order detonations potentially can serve as localized sources for groundwater contamination if positioned in recharge areas.

A time series investigation of the stability of nitramine and nitroaromatic explosives in surface water samples at ambient temperature.

We investigated the fate of nitramine and nitroaromatic explosives compounds in surface water to determine how surface water biogeochemistry affects the stability of explosives compounds. Five river water samples and 18.2 MOmega deionized water were spiked with 10 explosives compounds and the samples were held at ambient temperatures (20 degrees C) for 85 d. Surface water represented three rivers with a range of total organic carbon concentrations and two rivers draining glacial watersheds with minimal organic carbon but high suspended solids. 18.2 MOmega deionized water exhibited no explosives transformation. Nitroaromatic compound loss from solution was generally: tetryl>1,3,5-TNB>TNT>1,3-DNB>2,4-DNT. The HMX, RDX, 2,6-DNT, 2ADNT, and 4ADNT concentrations remained somewhat stable over time. The surface water with the highest total organic carbon concentration exhibited the most dramatic nitroaromatic loss from solution with tetryl, 1,3,5-TNB and TNT concentrations decreasing to below detection within 10d. The two water samples with high suspended solid loads exhibited substantial nitroaromatic explosives loss which could be attributable to adsorption onto fresh mineral surfaces and/or enhanced microbiologic biotransformation on mineral surfaces. An identical set of six water samples was spiked with explosives and acidified with sodium bisulfate to a pH of 2. Acidification maintained stable explosives concentrations in most of the water samples for the entire 85 d. Our results suggest sampling campaigns for explosives in surface water must account for biogeochemical characteristics. Acidification of samples with sodium bisulfate immediately following collection is a robust way to preserve nitroaromatic compound concentrations even at ambient temperature for up to three months.

Field Observations of the Persistence of Comp B Explosives Residues in a Salt Marsh Impact Area

Field observations of weathering Comp B (RDX/TNT 60/40) residue were made on a live-fire training range over four years. The Comp B residue was formed by low-order detonations of 120-mm mortar projectiles. Physical changes were the disaggregation of initially solid chunks into masses of smaller diameter pieces and formation of red phototransformation products that washed off with rain or tidal flooding. Disaggregation increased the surface area of the residue, thereby increasing the potential for dissolution. The bulk of the mass of Comp B was in the craters, but solid chunks were scattered asymmetrically up to 30m away.

Subsampling Variance for 2,4-DNT in Firing Point Soils

At 105-mm howitzer firing points, 2,4-DNT is detectable in the surface soils, but field sampling and laboratory subsampling uncertainty can be large during quantitation. The 2,4-DNT is in particulate form, within fibers or slivers of the nitrocellulose-based propellant. The slender fibers range up to 7.5 mm in length with masses of several 100 μ g. Size fractionation of a firing point soil revealed that most of the 2,4-DNT was in the 0.595- to 2.00-mm size range, although the bulk of the soil was less than 0.6 mm prior to grinding. Machine grinding for five minutes was needed to pulverize the propellant fibers sufficiently so that estimates of 2,4-DNT were reproducible in replicate analytical subsamples. To determine 2,4-DNT, we have adopted the practice of grinding firing point soils for five one-minute intervals, with time for heat dissipation between grinds, prior to obtaining individual or replicate 10-g subsamples.

Remediation methods for white phosphorus contamination in a coastal salt marsh

With the closure of many military bases worldwide and a closer scrutiny of practices on remaining bases, the environmental impact of the military is now an important consideration in the operation of bases. Many previously-unknown environmental problems related to chemicals are surfacing. White phosphorus, a chemical commonly used as an obscurant, is a chemical previously thought to be innocuous after use. In 1990, however, it was linked to the deaths of thousands of waterfowl at the Eagle River Flats impact area on Ft Richardson near Anchorage, Alaska, USA, and shortly after, a series of remedial investigations was initiated. This paper describes three of the remedial methods currently under investigation, namely enhanced in-situ remediation, pond draining through ditching or pumping, and dredging. These three approaches are best applied in different environments, but they can be used together or in conjunction with other strategies. Their impacts on the environment will vary as well. Experience with these remediation strategies has proven very useful in determining the direction that the clean-up effort at Eagle River Flats (ERF) should take. Dredging, an effective means of removing contaminated sediments for off-site remediation, has been shown to be too slow and expensive at the ERF because unexploded ordnance is present. Enhanced natural remediation is effective under favourable climatological conditions in areas that experience intermittent flooding, but desaturation of the sediments is critical to its effectiveness. Pond draining by blasting a ditch effectively removes waterfowl feeding habitat, but attenuation of the contaminant is inhibited because the ditch increases flooding frequency, and the habitat alteration is permanent. Pond pumping, where feasible, has shown great potential for the desaturating of wide areas of ERF, enabling the natural attenuation mechanism to progress. Further investigation will be necessary to confirm these initial conclusions and determine the overall effectiveness of all three methodologies. Methods developed over the course of this work may be applied to other remediation projects where in-situ volatilization can occur and limited disturbance of wetlands is critical.

White Phosphorus Contamination of an Active Army Training Range

Detonations of military ordnance will leave various amounts of chemical residue on training ranges. Significant adverse ecological effects from these residues have not been documented except for ordnance containing white phosphorus. At a military training range in Alaska, USA, the deaths of thousands of waterfowl due to poisoning from white phosphorus ordnance prompted a two-decade-long investigation of the extent of the contamination, remediation technologies, and methods to assess and monitor the effectiveness of the remediation. This paper gives an overview of these investigations and provides the outcome of the remediation efforts.

Using ice surfaces to decrease the impact of a remediation project.

Eagle River Flats is an estuarine salt marsh located on Fort Richardson, AK. It has been the main impact area for artillery training for over 60 years. In 1990, large reported waterfowl die-offs (>1,000 ducks/year) were attributed to white phosphorus residues in ponded and marsh areas from the detonation of military smoke munitions. A remediation strategy of temporary draining of contaminated ponded areas followed by capping of isolated locations was specified in the Record of Decision (RoD) by site regulators in 1998. Remediation by pumping of the ponded areas was carried out from 1997 until 2007, when the initial remedial action objectives were met. Many small, isolated locations remained contaminated, however, resulting in continued low rates of waterfowl mortalities. Capping these sites was thus required by the RoD to prevent waterfowl access to the contaminant. Our strategy was to conduct capping operations over the frozen salt marsh to reduce costs, minimize environmental impact, and improve safety while working in an active impact area. By mid-February, there is sufficient ice, continuous cold temperatures, and daylight to conduct operations. The process requires an unexploded ordnance technician to sweep the access routes and sites prior to plowing to expose the ice surface. Two days are allowed to freeze up and strengthen the roads. Geotextile is then laid at the pre-marked capping locations and a layer stone is piled over the Geotextile as capping material. When the ice melts in the spring, the stone is kept consolidated by the geotextile, settling over the contaminated area and isolating it from waterfowl. A test capping operation in 2007 was successful. A full-scale capping operation was carried out in February of 2008. The number of ducks killed by white phosphorus poisoning fell from 35 in 2007 to eight in 2008. The corresponding median mortality rate for the overall duck population fell from 0.9% to 0.3. Ground surveys of the treatment area indicated no adverse environmental impact. Further work was conducted in March of 2009 to address the remaining contaminated areas and to conduct minor maintenance. All capped areas have been sampled along their periphery to ensure completeness of coverage.

In-Situ Remediation of White Phosphorus in Wetlands

White phosphorus has been found to be the causal agent for massive waterfowl die-offs at the Eagle River Flats impact range on Ft. Richardson, Alaska. Research indicates that in-situ remediation of white phosphorus is possible if the sediments in which the contaminant persists can be desaturated and the temperature rises to where sublimation can occur. Several remediation methods have been studied at the Flats, the most promising of which is the pumped removal of ponded water using an automatic remote pumping system developed by the U.S. Army Cold Regions Research Engineering Laboratory (CRREL). This paper will describe the system, its deployment, and the results of the first year’s study.